A Short, but Dramatic Performance

Did you catch it this year? It’s a short, but dramatic one-act performance, and there’s not much advance publicity.

Wood Frogs – the earliest amphibian song of the spring. There may still be ice in some corners of their vernal pools, but unnecessary delay is not an option. Their vernal pools are beneficial to tadpoles because there are no fish present to eat them. However, these pools may not hold water year round. Males fertilize eggs as the female releases them, and then the tadpoles must hatch and mature before the pools dry up. It’s all quite urgent. 

Wood Frogs are forest dwellers, not surprisingly, and they live in solitary silence. As you may know, they can actually freeze during the coldest times in winter. Glucose replaces water that is drawn out of their organs and into their abdominal cavities so their organs are not damaged. It takes a little time to “thaw,” but when the process has completed, they can take to the stage.

Males respond to the early spring urgency by pouring in from surrounding woods to the vernal pools, and females follow shortly thereafter.

 

Males promptly begin calling, or “advertising.” I refer to these as "songs," but the proper term is “advertisement calls” - and advertising  is exactly what they are doing.

It’s an amphibian cacophony. The water bubbles and ripples with frogs, each attempting to out-sing the others. Their performances intensify as females arrive, and the chorus can be heard before the stage is even visible.  

So each spring I compulsively watch the weather forecast and balance that information against my academic schedule and all those other necessities that adult humans need to address…and hope there will be a point of convergence.

I’d heard and recorded Wood Frogs singing with Spring Peepers and a large chorus of Western Chorus Frogs at The Wilderness Center on March 24^th, but that’s in the southeast corner of Stark County near the Wayne County line. 



We only had to wait a little longer up here by Lake Erie.

I hurried to the wetland area at North Chagrin Reservation’s Wilson Mills trailhead on March 27th, as conditions seemed promising. Before I even reached the water I could hear that my guess was exactly correct this year! 



Not only could I hear Wood Frogs, but to my surprise, soon I could even see them! It wasn't just the usual part of a head or some eyes above the water, but the actual frogs. 

 

I went back after dark on the 28^th and again on the 29^th. More frogs were calling.



The marsh is on either side of the dirt trail, and it’s possible to get close to the frogs if one doesn’t mind sitting and kneeling on the ground. I was able to study their behavior in greater detail than I have in the past, as I can’t generally get close enough without the frogs simply going silent. Maybe I appear to be some kind of large, awkward wading bird with plans to eat them.

But they quickly determined that I was too slow and clumsy to be a threat to anything, and they generally ignored me. Some came right up to the edge of the water as if attracted to my flashlight. 

People often describe the Wood Frogs’ calls as sounding like quacking ducks. Do they? Two Mallards decided to add their voices to the Wood Frog chorus when I was recording. The Mallards’ calls are a little lower in pitch, but there’s a definite similarity in tone quality.

 
Because the water was shallow, I could even see them underwater, enabling me to observe how their behavior corresponds to their calls.

The single “quack” call is typically made when the male is in one place. He may move, then begin calling again. The cacophony results from multiple males calling at the same time but with no synchronization, unlike the back-and-forth of Western Chorus Frogs. 

I was finally able to observe the paired vocal sacs on the sides of their heads. They inflate and deflate quickly to make the emphatic “quack” call.

But I knew there were times I’d also hear a rapid series of calls from an individual male. What did that communicate? Since I could observe them more closely, I could see that consecutive calls accompanied the male swimming after another male or defiantly approaching one that had gotten too close.

Even if the frog himself wasn't quite visible, I could see the concentric circles of the ripples he generated during the confrontation.

I didn’t witness the details of male interactions with females, as there were generally a number of noisy, agitated males in the vicinity. When males and females were joined in amplexus (when the male holds onto the female from above and fertilizes the eggs that she releases) they generally were silent. 

A male might occasionally call if another male tried to break apart the amplexus bond. 

But in a week or a little longer, the excitement was over for another year and the Wood Frogs silently returned to the forest. Consider yourself fortunate when you spot one now, as their colors blend impressively well with the forest floor and low vegetation. 

As spring progresses, Spring Peepers and Western Chorus Frogs will still be singing as the Wood Frogs depart, and Leopard Frogs and Pickerel Frogs will begin calling shortly thereafter. Green Frogs and American Toads follow, finallyjoined by Bullfrogs and the beautiful Gray Treefrogs.

But the Wood Frogs are a voice of spring’s first challenge to winter: urgent, dramatic, and so welcome.